If you own this game, on your Game Room on your XBOX, then it will be much easier to win all three medals. If you had not, then this may be a little more difficult than expected. You can however, get quite simply the point medal (5000 points), and the time (30 minutes) to after that of survival you will need a little training.
Finally I said that you do not need to get the 3 gold medals to unlock this achievement ;)